A pivotal sash window adapted for installation in a master frame of a sash window assembly is well-known. The sash window assembly typically has opposed, vertically extending guide rails to enable vertical reciprocal sliding movement of the sash window in the master frame while cooperatively engaged with the guide rails. The sash window has a top sash rail, a base and pair of stiles cooperatively connected together at adjacent extremities thereof to form a rectangular sash frame. Typically, a pair of spaced tilt-latches are installed on, or in, opposite ends of the top sash rail.
Each tilt-latch is generally comprised of a housing having an outward end opening and a latch bolt disposed within the housing. A spring disposed within the housing generally biases the latch bolt through the outward end opening to engage the guide rails of the master frame. A control button on the latch bolt extends through an opening on the upper surface of the housing. An operator can use his finger to engage the button and actuate the latch bolt wherein the latch bolt is retracted into the housing. This releases the latch bolt from the guide rail. When the latch bolts of the opposed tilt-latches are actuated simultaneously, the sash window can then be pivoted.
Certain tilt-latches have been surface mounted on the top sash rail, such as shown in U.S. Pat. Nos. 4,837,975 and 4,901,475, and assigned to Ashland Products, Inc., the assignee of the present invention. Other tilt-latches have been flush-mounted in the top sash rail, such as shown in U.S. Pat. No. 5,139,291, also assigned to Ashland Products, Inc.
Irrespective of the type of tilt-latch, typically, only the spring biasing force prevents the latch bolt from being retracted into the housing. Finger pressure overcomes this biasing force to actuate the latch bolt. In certain instances, however, the latch bolts on the tilt-latches can be inadvertently actuated. In some applications, it is desirable to selectively prevent actuation of the latch bolt.
U.S. Pat. No. 5,096,240, also assigned to Ashland Products, Inc., discloses a tilt-latch for a pivotal sash window assembly. The tilt-latch has a lock button to selectively prevent retraction of the latch bolt. While this patent discloses a tilt-latch having a functional means to selectively prevent retraction of the latch bolt, its structure requires a number of cooperating parts. It also requires a separate key or tool to position the lock button accordingly.
The present invention is provided to solve these and other problems.